In computer and telecommunications networks, presence information is a status indicator that conveys ability and willingness of a potential communication partner, for example a user, to communicate. A user's client provides presence information (presence state) via a network connection to a presence service, which is stored in what constitutes his/her personal availability record (called a presentity) and can be made available for distribution to other users (called watchers) to convey his/her availability for communication. Presence information has wide application in many communication services and is one of the innovations driving the popularity of instant messaging or recent implementations of voice over IP (VoIP) clients in the present day telecommunication scenario.
The presence service is a service that enables the collection of communication related information of a person, followed by the dissemination of the collected information of the person of interest to other persons. Presence based interactive communication services facilitate more efficient and effective communication sessions by enabling presentities to publish in real time, their presence information (such as, the availability, activity, local time, location, current status of the active devices/applications, etc.), and their preference information (e.g., device preferences) to presence watchers. The presence and preference information improves the efficiency of establishing various types of communication sessions, such as voice, text and multi-media communication.
FIG. 1 illustrates the basic architecture of existing art of presence service. The target person of interest in the presence service is called as presentity and the communication related information is called as presence information. Each presence source collects its view of the presentity's presence information, and then delivers it to the presence server using SIP PUBLISH, a method used for publishing event state information such as presence event and reg. events as defined in RFC3903 “Session Initiation Protocol (SIP) Extension for Event State Publication”, A. Niemi, October 2004. The presence server composes the presentity's presence information from presence sources and delivers the aggregated presence information of the presentity to the persons who have requested for the same. The persons who have interests of the presentity's presence information are called watchers and they use the presence event subscription and notification for the requests and delivery of the presentity's presence information, according to RFC3856 “A Presence Event Package for the Session Initiation Protocol (SIP)”, J. Rosenberg, August 2004. When a watcher subscribes to presence event package for the presence information of a presentity, he/she can also include in the subscription request the event notification filter as per RFC4660 “Functional Description of Event Notification Filtering”, H. Khartabil, et al. September 2006, such that he/she can receive only the interested part of the presence information, and not the entire chunk. Upon receiving this presence subscription request from the watcher, the presence server authorizes the request to decide whether the presentity allows the watcher to subscribe his/her presence information and if allows, what parts of the presence information is allowed to be disseminated and sent to the watcher. Upon successful authorization, the presence server delivers the authorized parts of the presence information of the presentity to the watcher using the presence event notification.
In the state of the art literature, the US published patent application titled “System and method for utilizing a presence service to advertise activity availability” describes a system and method for advertising over a network an invitation to engage in at least one activity is described. In one embodiment, a presence service on the network receives from an inviting presence client activity information related to at least one activity the inviting presence client is interested in participating. The presence service then updates a tuple associated with the inviting presence client to include the information related to the activity, and sends the invitation to engage in the activity to at least one other presence client on the network.
In short, the above-mentioned prior art literature describes a system and method for advertising an activity to presence clients over a network. A first presence client sends activity information to the presence service on the network. The presence service then updates a tuple associated with the first presence client to include the activity information. The presence service then sends an invitation to other presence clients on the network. Other presence clients can subscribe to the activity upon receiving the invitation. That is, the patent application describes a presence client sharing its current or future availability status to other presence clients. However, it does not explicitly mention sending of any advertisements about newly added presence information by the presentity.